RS232 TEST


        These programs will test various RS232 hardware functions.  If they run 
OK then The Weak Link and The $25 Network should run on the hardware.  

  1) hook up the cable between machines
  2) run  TMT.COM on one machine
  3) run  RCV.COM on the other machine
  4) the screen will display all errors

RCV runs continuosly until any key is pressed.  It prints "z" characters while 
the other machine is dormant. TMT runs once and then exist to DOS.  COMPAT also 
runs once and then exits to DOS.  All three programs assume you are using COM1 
to communicate. If not then enter the COM number on the command line when you 
run the program: 


        A>TMT COM2

        or

        A>RCV COM2



        The TMT program initiates the test.  The 1st test is to make sure the 
COM number you specify is really installed.  Then each RS232 card that is 
installed is printed out along with its hardware port address.  The total 
number of ports is then printed. (To find out what ports are on a machine, run 
RCV.)  The 2nd test is of the data channel.  If this test fails then the cable 
may be bad, or it may not be a nul modem cable, or it may be hooked up to the 
wrong port.  MAKE SURE YOU DO NOT HAVE TWO CARDS INSTALLED AT THE SAME PORT 
ADDRESS. Unfoutunately a program cannot test for this possibility.  But with 
the proliferation of Multi I/O cards it is a common mistake to put two 
different cards in a computer with the same RS232 port address. If your 
computer has more RS232 connectors than the number of ports RCV shows you have 
installed then it is possible you have 2 ports at one address.  

        After the data line test is the DSR-DTR line test.  If this test fails 
then the cable you have is probably missing these two lines or they are not 
crossed between the machines.  

        The last test is a string transfer from RCV to TMT.   The test string 
will be printed to the TMT screen.  If this message appears then the test is 
good and "CHECK OK" will be printed to both screens.  This program may fail the
first couple of times even on good hardware so be sure to run it several times 
to make sure.  As soon as it passes once it should never fail thereafter unless 
the hardware is reconfigured or powered down.

        COMPAT is a secondary test for The $25 Network.  It should be run right 
after TMT while RCV is still running on the other machine.  RCV should be 
printing "z" characters on the other machine's screen.  COMPAT also assumes  
you are using COM1, so if not then you must enter the correct COM port on the 
command line: 

        A>COMPAT COM2

COMPAT also tests the hardware interrupt used by the RS232 (Serial card) port 
so you must specify the interrupt your machine is using.  The interrupt will 
almost always be INT12 if you are using COM1, and INT11 if you are using COM2.
The interrupt is also specified on the command line:

        A>COMPAT COM2 INT11









Some manuals will mention IRQ0 thru IRQ7 which refer to the interrupt chip not 
the actual CPU interrupt used (add 8 to IRQ# to get INT# if IRQ < 8).
COMPAT will print messages to the screen to inform you of its progress. If it 
finishes "--> GOOD." then The $25 Network will probably run on that machine.
Next, duplicate the test by running the other direction, ie, put RCV on the 
machine which just ran TMT and COMPAT, etc.


        If you cannot get the network to run on your system even after the 
diagnostics tests run ok then you will have to break your system down to 
a bare bones system in order to locate the problem.  Remove all cards which are 
not absolutely necessary.  It would be best to have only the motherboard, the 
display adapter, a floppy controler, and ONE serial port.  If you have two 
serial ports installed then, if possible, remove or diable the second serial 
port.  If you are familiar with removing ICs then remove the 8250 or 16450 from 
the second serial port.  When you get the network running then you can start 
putting things back together one at a time, testing after each addition.  Then 
you will probably find the culprit.

        The main sources of problems are, in order:

        1) Cable!
           Make sure the 5 lines needed are wired correctly and only those 5 
           lines are wired.  

        2) Interrupts.
           Often there are two serial cards using the same interrupt (11 or 12).
           The network cannot share its interrupt with anything else.

        3) Mice.
           Some mouse setups cause the network problems.  They may use the
           same interrupt.

        5) Big hard disks
           Some hard disks > 32 Mb have been formated with special software
           which sets up sector sizes other than 512 bytes.  Such a disk cannot 
           be read or written to over the network.

        4) Math coprocessors.
           On rare occations a 8087 or 80287 causes a problem.


        If you encounter errors which you cannot decipher or fix then please 
don't hesitate to call. 


                                        Don Jindra, Owner
                                        Information Modes
                                        P.O. Drawer F
                                        Denton, Texas  76202
                                        Ph. 817-387-3339